The aim of this proposal is to acquire compatible equipment to upgrate an existing flow cytometry and cell sorting facility. The major users of this facility apply flow cytometry and cell sorting to a number of basic research areas, including: cloning of different functional subtypes of human T lymphocytes with anti-tumor and anti-HLA activity; mechanisms of alopecia; differentiation of bone marrow cells; effects of estrogens on breast cancers; depressed immune function in agen; mechanism of rheumatoid arthritis; and effects of immunotoxins on human lymphoid cells. Need for improved instrumentations arises from a number of research aims which can be approached with difficulty, if at all, with the existing equipment. The new equipment requested will be added to the existing FACS-IV flow cytometer and cell sorter. 1) Second argon ion laser and tunable dye head with third fluorescence detection channel. These items will allow three-color immunofluorescence, dual fluorochrome analysis witih forward and 90 degree light scatter, and studies on viable cells requiring cell cycle analysis and immuno-fluorescence. 2) Consort 40C and graphics plotter. The Consort 40C is a high speed, user accessible computer supplied with software to allow acquisition and analysis of multiparameter, list mode data. Without this computer the full capabilities of the existing and requested equipment will not be realized. The graphics plotter is needed to provide legible hard copy output of information processed by the Consort 40C.